The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometric size (i.e., the smallest component that can be created using a fabrication process) has decreased. Such advances have increased the complexity of processing and manufacturing ICs. For these advances, similar developments in IC processing and manufacturing are needed.
Micro-electro mechanical system (MEMS) devices have recently been developed. MEMS devices include devices fabricated using semiconductor technology to form mechanical and electrical features. The MEMS devices may include a number of elements (e.g., movable elements) for achieving mechanical functionality.
MEMS applications include microphone, motion sensors, pressure sensors, printer nozzles, or the like. Other MEMS applications include inertial sensors, such as accelerometers for measuring linear acceleration and gyroscopes for measuring angular velocity. Moreover, MEMS applications may extend to optical applications, such as movable mirrors, and radio frequency (RF) applications, such as RF switches and the like.
Although existing devices and methods for forming MEMS devices have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects.